An apparatus, as well as a method, brings a surface of a substrate into contact with a polishing pad that has a window, causes relative motion between the substrate and the polishing pad, and directs a light beam through the window so that the motion of the polishing pad relative to the substrate causes the light beam to move in a path across the substrate. Light beam reflections from the substrate are detected, and used to determine polishing parameters, detect process repeatability, and qualify processes.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A method of determining polishing parameters, comprising: bringing a surface of a substrate into contact with a polishing pad that has a window; causing relative motion between the substrate and the polishing pad; directing a light beam through the window, the motion of the polishing pad relative to the substrate causing the light beam to move in a path across the substrate; detecting light beam reflections from a layer in the substrate; generating reflection data associated with the light beam reflections; displaying the reflection data from a scan of the light beam across the substrate; and selecting polishing parameters to provide uniform polishing of the substrate based on the displayed reflection data.
2. The method of claim 1, wherein the displayed reflection data shows the reflectivity of the substrate as the light beam scans across the substrate.
3. The method of claim 1, wherein the reflectivity of the substrate as is displayed in real-time during polishing.
4. The method of claim 3, wherein the layer is a metal.
5. The method of claim 1, wherein the reflection data includes a plurality of intensity measurements made at a plurality of positions along the path across the substrate.
6. The method of claim 5, further comprising calculating a radial position relative to the center of the substrate for each intensity measurement.
7. The method of claim 1, further comprising dividing the reflection data into a plurality of radial ranges, and determining which radial range is the last portion to be completely polished.
8. The method of claim 1, wherein the displayed reflection data forms at least one transient signal graph.
9. The method of claim 8, wherein each transient signal graph consists of reflection data from a single sweep of the window beneath the substrate.
10. The method of claim 9, wherein the layer is a metal.
11. A method of generating endpoint parameters, comprising: polishing a first substrate; detecting light beam reflections during polishing the first substrate to generate a first plurality of intensity measurements; determining a radial range to use for endpoint detection from the first plurality of intensity measurements; polishing a second substrate; detecting light beam reflections during polishing of a layer in the second substrate to generate a second plurality of intensity measurements; calculating a radial position relative to the center of the second substrate for each of the second intensity measurements; determining a polishing endpoint from those second intensity measurements which are within the radial range.
12. The method of claim 11, wherein determining the radial range includes determining the last portion of the first substrate to be completely polished.
13. The method of claim 11, further comprising determining at least one process parameter for polishing of the second substrate from the first plurality of intensity measurements.
14. A method of determining process uniformity, comprising: detecting light beam reflections during polishing of a layer in a first substrate; detecting light beam reflections during polishing of a layer in a second substrate; generating reflection data associated with the light beam reflections; displaying reflection data from a first scan of the light beam across the first substrate; displaying reflection data from a second scan of the light beam across the second substrate; and comparing the reflection data from the first scan to the reflection data from the second scan to determine process uniformity.
15. The method of claim 14, further comprising changing a polishing consumable between the polishing of the first and second substrates.
Cooperative Patent Classification codes for this invention. Click any code to explore related patents in that topic.
June 8, 2000
October 2, 2001
Browse 5M+ US patents with plain-English claim translations and AI-generated analysis.